Chinese e-commerce giant Alibaba is set to raise as much as $24 billion dollars in its initial public offering, valuing the company at some $150 billion, which would make it the biggest IPO ever in terms of both valuation and amount raised.

(For the record, Yahoo holds a 22 percent stake in Alibaba, and plans to sell some of that holding in the offering.) But while the massive IPO could be seen as a good sign for markets and for the global economy, some exactly argue that it could actually mark a top to the long bull market in U.S. stocks.

“This is interesting for the market, but I do think it’s a little worrisome at some of the levels that we’re getting at,” said Gina Sanchez of Chantico Global.

It’s not that she doesn’t think there’s enough global liquidity to support the offering. Rather, she thinks the offering indicates that there is far too much global liquidity.

And whether or not the Alibaba IPO indicates a top, it should be no surprise that big IPOs tend to come when investor confidence is high. After all, investment bankers don’t look to unveil big offerings at times when most investors are feeling cautious.